Improved boom and gaff joint



UNITED STATES PATENT OFFICE.

IM PROVED BOOM AND GAFF JOINT.

Specification forming part of Letters Patent No. 45,625, dated December 27, 1864.

To all whom it may concern Beit known that I, JOSEPH W. Noncnoss, of Middletown, in the county of Middlesex and State of Connecticut, have invented a new and improved Boom and Graff-Joint;v and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable those skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l represents a side elevation of this invention. Fig. 2 is a horizontal section of the same. Fig. 3 is a front elevation of a portion of the joint.

Similar letters of reference indicate corresponding parts.

This invention consists in a boom or gaff joint with a triple motion, or composed of a universal joint, in combination with a swiveljaw, in such a manner that the boom or gaft' is free to accommodate itself to the position of the sail and sheet without straining thejoint. The universal joint is so arranged that the fulcra'of the same are situated in one plane, and a change of the position of the boom does not increase the strain on the joint as it does with joints of the ordinary construction, and when this joint is used fora gait-joint it is applied in combination with a slide secured to the mast, so that the gaff can be raised and lowered without obstruction.

The ordinary method of attaching a boom or gaft' to the mast of a vessel is by means of wooden jaws. There are several objections to this method, the principal being the chafing of the mast, and that the jaws are frequently broken by cramping against the mast. Another method is by an ordinary universal joint or a double joint, the fulcra of which are situated in different planes,` one farther from the mast than the other. These joints are frequently broken from two causes, first, the sheet on the boom is necessarily on the under side of the same, and when the boom jibes, or when the sail is shifted from one side to the other, the boom being unable to revolve, twists the joint so as to causeit to break. The other cause is, one joint being situated outside of Lthe other, as soon as the boom or gaff is raised above a level a great strain is brought on the inside joint and frequently causes it to break.

All these objections are avoided by the new boom and gait' joint which forms the subjectmatter of this present invention, and which is composed of three joints, A B C. The first joint, A, is composed of a swivel, a, which is iitted into a grooved bracket, c', secured to the mast by any suitable means, said swivel being provided with a groove, a2, as shown in Fig. 2 of the drawings, to receive the projecting edge of the socket in the bracket. By this arrangement said swivel is firmly held in place, and yet it is enabled to revolve freely in a vertical plane. jaws, a3, which form the bearings for the fulcrum-pin `b of the second joint B, which is composed of a cup or hemisphere, b. The third or last joint Gis formed of a forked arm, c', secured to the inner end of the boom or gait', and made to straddle the cup or hemisphere b being connected thereto by a pin, c, which forms the fulcrnm of the joint C.

The fulcrum-pins b and c of the joints B O are situated in the same vertical plane, or at the same distance from the mast, so that a change of the position ofthe boom or gaifdoes not produce any increase of strain on either of the joints.

In jibing, the joint A allows the boom to revolve and to accommodateitself to the position of the sail and sheet, and thereby relieves the gre :t strain brought upon it by the check and momentum, and the joints B O permit the boom or gai' to swing freely in a vertical or horizontal direction, and all the difficulties attending to boom er ga joints of the ordinary construction are done away with.

When used for a gait-joint, the swivel a must be tted into a grooved rail secured to the mast, so that said gait' can be raised or lowered as may become necessary.

I claim as new and desire to secure by Letters Patentl. A boom or gaf'joint with a triple motion, substantially as and for the purpose set forth.

2. The swivel a, in combination with the bracket or grooved rail a', and with a boom or gah constructed and operating substantially W. W. WILcoX, M. M. LIVINGSTON.

From said swivel rise two 

